This invention relates generally to interconnection and switching systems, and, more particularly to optical switching systems including switched-grating and opto-electronic layers.
There are many advantages of “transparent” (purely optical) optical switches. Using transparent switches optical carriers may be routed from input fiber to output fiber without the necessity of converting the signal to electronic form and reproducing the optical signal. This can also provide savings when bandwidths are upgraded, since there is no electronic layer to upgrade. However, there are hidden complexities in the transparent switch approach when used with WDM and DWDM carriers. For example, if two signals arriving on different fibers on the same wavelength channel are switched to the same output fiber, there is a wavelength conflict. To address such conflicts, “wavelength shifting” technologies are being developed. Many of these “wavelength shifting” technologies add a tremendous complexity to the overall switch.
The “opaque optical switch” model (all-electronic or optical-to-electronic-to-optical model) carries its complexity up front. Once this complexity is provided the switch operates in a simple and robust fashion. However, all-electronic optical crossconnects are encumbered by having to propagate high bandwidth electronic signals over relatively large distances as required in a crossconnect.
There is a need for an optical switch that provides the advantages of both the “transparent” and the “opaque” optical switches.
It is therefore an object of this invention to provide an optical switching/routing system that has the advantages of both the “transparent” and the “opaque” optical switches.
It is a further object of this invention to reduce the hidden complexities of “transparent” optical switches.